Biplane angiography/CT apparatus

ABSTRACT

In order to provide a biplane angiography/CT apparatus which can alternately perform CT imaging and simultaneous angiographic imaging in frontal and lateral planes, and which does not make a subject feel discomfort and has improved safety, a lateral arm  30  for performing angiographic imaging in the lateral plane is provided in addition to a frontal arm  20  and a CT gantry  40 . Moreover, a control apparatus  50  is provided for, when angiographic imaging is to be performed, retracting the CT gantry  40  to a position not hindering the angiographic imaging and moving the frontal and lateral arms  20  and  30  to an angiographic imaging position, and when CT imaging is to be performed, retracting the frontal and lateral arms  20  and  30  to positions not hindering the CT imaging and moving the CT gantry  40  to a CT imaging position.

BACKGROUND OF THE INVENTION

The present invention relates to a biplane vascular imaging(angiography)/CT apparatus, and more particularly to a biplaneangiography/CT apparatus which can alternately perform CT imaging andsimultaneous angiographic imaging in two planes in theanterior-posterior direction, i.e., the frontal direction and in theleft-right direction, i.e., the lateral direction, of a subject, andwhich does not make the subject feel discomfort and has improved safety.

European Patent Laid Open No. EP0919185A1 discloses an angiography/CTapparatus comprising a top plate for laying a subject, a frontal armcomprising an X-ray tube and an X-ray image receiving device forperforming angiographic imaging vertically across the subject laid onthe top plate, a CT gantry comprising an X-ray tube and an X-raydetector for performing CT imaging on the subject laid on the top plate,and top plate moving means which allows the top plate to horizontallymove.

According to this angiography/CT apparatus, the angiographic imaging isachieved in a frontal plane by moving the top plate to the position ofthe frontal arm using the top plate moving means for moving the topplate in its longitudinal direction. The CT imaging is achieved bymoving the top plate to the position of the CT gantry using the topplate moving means. Therefore, the angiographic imaging in the frontalplane and the CT imaging can be alternately performed in a cycle of, forexample, five minutes, by alternately moving the top plate between thetwo positions.

Angiographic imaging may be performed not only in the frontal plane butalso in a lateral plane horizontally across the subject. Thus, there isa need for an apparatus which can alternately perform CT imaging andsimultaneous angiographic imaging in two planes, i.e., the frontal andlateral planes.

However, bi-directional angiographic imaging involves a frontal arm anda lateral arm extending in two directions. If the CT imaging apparatusand these biplane apparatuses are simply arranged in the longitudinaldirection of the top plate, the overhead traveling lateral arminterferes with the CT gantry.

The CT imaging apparatus is therefore placed at a position opposite tothe biplane apparatuses across a patient table (i.e., at 180°) or placedat 90°, and the top plate is rotated and moved in its longitudinaldirection between the apparatuses to accommodate all these apparatuses.

The above configuration, however, requires the top plate to rotate withthe subject catheterized for injecting a contrast agent, and the subjectmay be exposed to danger and stress.

SUMMARY OF THE INVENTION

The present invention provides a biplane angiography/CT apparatus whichalternately performs CT imaging and simultaneous angiographic imaging byarms extending in two directions, i.e., a frontal arm and a lateral arm,and which does not make a subject feel discomfort and has improvedsafety.

In accordance with a first aspect of the invention, there is provided abiplane angiography/CT apparatus comprising: a top plate for laying asubject; a frontal arm comprising an X-ray tube and an X-ray imagereceiving device for performing angiographic imaging vertically acrossthe subject laid on the top plate; a lateral arm comprising an X-raytube and an X-ray image receiving device for performing angiographicimaging horizontally across the subject laid on the top plate; a CTgantry comprising an X-ray tube and an X-ray detector for performing CTimaging on the subject laid on the top plate; and control means forretracting the CT gantry to a position not hindering the angiographicimaging and moving the frontal and lateral arms to an angiographicimaging position based on a command an operator, and for retracting thefrontal and lateral arms to positions not hindering the CT imaging andmoving the CT gantry to a CT imaging position based on a command by theoperator.

The biplane angiography/CT apparatus of the first aspect is providedwith a lateral arm for performing angiographic imaging in a lateralplane, in addition to a frontal arm and a CT gantry. This allowssimultaneous angiographic imaging in two planes, i.e., the frontal andlateral planes. Moreover, when angiographic imaging is to be performed,the CT gantry is retracted to a position not hindering the angiographicimaging and the frontal and lateral arms are moved to an angiographicimaging position, and when CT imaging is to be performed, the frontaland lateral arms are retracted to positions not hindering the CT imagingand the CT gantry is moved to a CT imaging position. Thus, even whenmovement of the top plate is minimal, interference of the frontal andlateral arms with the CT gantry can be prevented, and simultaneousangiographic imaging in two planes, i.e., the frontal and lateralplanes, and CT imaging can be alternately performed. Furthermore, sincethe need to move the top plate is eliminated, the subject is protectedfrom discomfort, and additionally safety is improved.

In accordance with a second aspect of the invention, there is provided abiplane angiography/CT apparatus comprising: a top plate for laying asubject; a frontal arm comprising an X-ray tube and an X-ray imagereceiving device for performing angiographic imaging vertically acrossthe subject laid on the top plate; a lateral arm comprising an X-raytube and an X-ray image receiving device for performing angiographicimaging horizontally across the subject laid on the top plate; a CTgantry comprising an X-ray tube and an X-ray detector for performing CTimaging on the subject laid on the top plate; top plate moving means forallowing the top plate to horizontally move in its longitudinaldirection; frontal arm swiveling means for allowing the frontal arm toswivel around a certain axis; lateral arm moving means for allowing thelateral arm to move in a certain direction; and CT gantry moving meansfor allowing the CT gantry to move in a certain direction.

The biplane angiography/CT apparatus of the second aspect is providedwith a lateral arm for performing angiographic imaging in a lateralplane, in addition to a frontal arm and a CT gantry. This allowssimultaneous angiographic imaging in two planes, i.e., frontal andlateral planes. Moreover, the above configuration especially reducesinterference of the CT gantry with the frontal and lateral arms.Specifically, the CT gantry is retracted to a position not hindering theangiographic imaging and the lateral arms can be moved to anangiographic imaging position, and the frontal and lateral arms areretracted to positions not hindering the CT imaging and the CT gantrycan be moved to a CT imaging position. Thus, even when the movement ofthe top plate is minimal, interference of the frontal and lateral armswith the CT gantry can be prevented. The subject is thus protected fromdiscomfort due to the movement of the top plate.

It is preferred that a switch be provided on the control means for theoperator to input the command to retract the CT gantry to the positionnot hindering the angiographic imaging.

Moreover, it is preferred that a switch be provided on the control meansfor the operator to input the command to move the frontal and lateralarms to the angiographic imaging position.

Alternatively, it is preferred that a switch be provided on the controlmeans for the operator to input the command to retract the CT gantry tothe position not hindering the angiographic imaging and to move thefrontal and lateral arms to the angiographic imaging position.

In addition, it is preferred that a switch be provided on the controlmeans for the operator to input the command to retract the frontal andlateral arms to the positions not hindering the CT imaging.

Moreover, it is preferred that a switch be provided on the control meansfor the operator to input the command to move the CT gantry to the CTimaging position.

Alternatively, it is preferred that a switch be provided on the controlmeans for the operator to input the command to retract the frontal andlateral arms to the positions not hindering the CT imaging and to movethe CT gantry to the CT imaging position.

In addition, the lateral arm moving means may be configured tohorizontally move the lateral arm in the longitudinal direction of thetop plate, and the CT gantry moving means may be configured tohorizontally move the CT gantry in the transverse direction of the topplate.

Alternatively, the lateral arm moving means may be configured tohorizontally move the lateral arm in the transverse direction of the topplate, and the CT gantry moving means may be configured to horizontallymove the CT gantry in the longitudinal direction of the top plate.

The lateral arm moving means may be configured to rotate the lateral armaround the longitudinal direction of the top plate.

The CT gantry moving means may be configured to horizontally turn the CTgantry.

The lateral arm moving means may be configured to horizontally turn thelateral arm.

The top plate is preferably configured to be vertically movable so thesubject can easily climb on and off the top plate.

Moreover, the top plate is preferably configured to be horizontallyrotatable so the subject can easily climb on and off the top plate.

The lateral arm may be configured to be swung up to the ceiling toprevent interference with the CT gantry.

According to the biplane angiography/CT apparatus of the presentinvention, since a lateral arm for performing angiographic imaging in alateral plane is provided in addition to a frontal arm and CT gantry,simultaneous angiographic imaging in two planes, frontal and lateral, ispossible. Moreover, when angiographic imaging is to be performed, the CTgantry is retracted to a position not hindering the angiographic imagingand the frontal and lateral arms are moved to an angiographic imagingposition, and when CT imaging is to be performed, the frontal andlateral arms are retracted to positions not hindering the CT imaging andthe CT gantry is moved to a CT imaging position. Thus, even whenmovement of the top plate is minimal, interference of the frontal andlateral arms with the CT gantry can be prevented, and simultaneousangiographic imaging in two planes, i.e., the frontal and lateralplanes, and CT imaging can be alternately performed. Furthermore, sincethe movement of the top plate is minimal, the subject is protected fromdiscomfort, and additionally safety is improved.

Further objects and advantages of the present invention will be apparentfrom the following description of the preferred embodiments of theinvention as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a biplane angiography/CT apparatus inaccordance with a first embodiment.

FIG. 2 is a perspective view of the biplane angiography/CT apparatus inaccordance with the first embodiment in which the CT gantry is moved toa CT gantry parking position and the frontal and lateral arms are movedto a biplane angiographic imaging position.

FIG. 3 is a perspective view of the biplane angiography/CT apparatus inaccordance with the first embodiment in which the frontal and lateralarms are moved to the frontal and lateral arm parking positions and theCT gantry is moved to a CT imaging position.

FIG. 4 is a flow chart of a biplane angiography moving process by thebiplane angiography/CT apparatus in accordance with the firstembodiment.

FIG. 5 is a flow chart of a CT moving process by the biplaneangiography/CT apparatus in accordance with the first embodiment.

FIG. 6 is a perspective view of a biplane angiography/CT apparatus inaccordance with a second embodiment.

FIG. 7 is a perspective view of a biplane angiography/CT apparatus inaccordance with a third embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in more detail withreference to embodiments shown in the accompanying drawings.

FIRST EMBODIMENT

FIG. 1 is a perspective view of a biplane angiography/CT apparatus 100in accordance with a first embodiment of the present invention.

The biplane angiography/CT apparatus 100 comprises: an imaging tableapparatus 10 comprising a top plate 11 for laying a subject and a topplate driving apparatus 12 which allows the top plate 11 to horizontallymove in its longitudinal direction and to vertically move; a frontal arm20 comprising an X-ray tube 22 and an X-ray image receiving device 21for performing angiographic imaging vertically across the subject laidon the top plate 11; a lateral arm 30 comprising an X-ray tube 32 and anX-ray image receiving device 31 for performing angiographic imaginghorizontally across the subject laid on the top plate 11; a CT gantry 40comprising an X-ray tube 41 and an X-ray detector 42 for performing CTimaging on the subject laid on the top plate 11; and control apparatus50 for retracting the CT gantry 40 to a position not hinderingangiographic imaging and moving the frontal and lateral arms 20 and 30to an angiographic imaging position based on a command by an operator,as shown in FIG. 2, and for retracting the frontal and lateral arms 20and 30 to respective positions not hindering CT imaging and moving theCT gantry 40 to a CT imaging position based on a command by theoperator, as shown in FIG. 3.

The X-ray tube 22 and X-ray image receiving device 21 of the frontal arm20 are attached respectively to the ends of a frontal C arm 23. Thefrontal C arm 23 is supported on a horizontal swivel base 24 placed onthe floor. The frontal C arm 23 is rotatable along its arc.

The X-ray tube 32 and X-ray image receiving device 31 of the lateral arm30 are attached respectively to the ends of a lateral C arm 33. Thelateral C arm 33 is supported by a ceiling rail 35 suspended from theceiling, and is horizontally movable along the ceiling rail 35. Theceiling rail 35 extends in the longitudinal direction of the top plate11. That is, the lateral C arm 33 is horizontally movable in thelongitudinal direction of the top plate 11. Moreover, the lateral C arm33 is rotatable along its arc.

The CT gantry 40 is supported on a floor rail 45 disposed on the floor,and is horizontally movable along the floor rail 45. The floor rail 45is extended in the transverse direction of the top plate 11. That is,the CT gantry 40 is horizontally movable in the transverse direction ofthe top plate 11.

In other words, the present embodiment is configured so that the lateralarm 30 is horizontally moved in the longitudinal direction of the topplate 11 and the CT gantry 40 is horizontally moved in the transversedirection of the top plate 11.

The control apparatus 50 has a monitor function of constantly monitoringthe position, angle and height of the top plate 11, the position andangle of the frontal arm 20, the position and angle of the lateral arm30, and the position and tilt angle of the CT gantry 40. Thus, thecontrol apparatus 50 interlock-controls the present apparatus and thesubject to maintain safety, and produces alarms and operation guidanceas necessary.

FIG. 4 is a flow chart of a biplane angiography moving process executedby the control apparatus 50.

In Step B1, the operator depresses a CT gantry parking switch providedon the control apparatus 50.

In Step B2, a decision is made whether the CT gantry 40 interferes withthe frontal arm 20, lateral arm 30 or top plate 11 when the CT gantry 40is moved to a CT gantry parking position, as shown in FIG. 2, at whichthe CT gantry 40 does not collide with the top plate 11 moved in thelongitudinal direction, and which is a position apart from the top plate11 in its transverse direction by a certain distance. If interferencedoes not occur, the process goes to Step B3; otherwise to Step B7.

In Step B3, the CT gantry 40 is moved to the CT gantry parking positionas shown in FIG. 2.

In Step B4, the operator confirms that the CT gantry 40 has been movedto the CT gantry parking position shown in FIG. 2, and then the operatordepresses a frontal/lateral arm moving switch provided on the controlapparatus 50.

In Step B5, a decision is made whether the frontal and lateral arms 20and 30 interfere with the CT gantry 40 or top plate 11 when the frontaland lateral arms 20 and 30 are moved to a biplane angiographic imagingposition, as shown in FIG. 2, at which the arms 20 and 30 are positionedvertically and horizontally across the top plate 11. If interferencedoes not occur, the process goes to Step B6; otherwise to Step B7.

In Step B6, the frontal and lateral arms 20 and 30 are moved to thebiplane angiographic imaging position shown in FIG. 2. Then, the processis terminated.

In Step B7, warning is given that the movement is not permissiblebecause of interference. Then, the process is terminated.

FIG. 2 is a perspective view in which the CT gantry 40 is moved to theCT gantry parking position and the frontal and lateral arms 20 and 30are moved to the biplane angiographic imaging position.

Because the CT gantry 40 has been moved to the CT gantry parkingposition, the lateral arm 30 can be moved to the biplane angiographicimaging position without interfering with the CT gantry 40. Then, thefrontal arm 20 performs angiographic imaging in a frontal plane and thelateral arm 30 performs angiographic imaging in a lateral plane at thebiplane angiographic imaging position. Thus, simultaneous angiographicimaging in two planes, frontal and lateral, is achieved.

FIG. 5 is a flow chart of a CT moving process executed by the controlapparatus 50.

In Step C1, the operator depresses a frontal/lateral arm parking switchprovided on the control apparatus 50.

In Step C2, a decision is made whether the frontal and lateral arms 20and 30 interfere with the CT gantry 40 or top plate 11 when the frontaland lateral arms 20 and 30 are moved to frontal and lateral arm parkingpositions which lie in the longitudinal direction of the top plate 11,as shown in FIG. 3, and which do not hinder the CT imaging. Ifinterference does not occur, the process goes to Step C3; otherwise toStep C7.

In Step C3, the frontal and lateral arms 20 and 30 are moved to thefrontal/lateral arm parking positions shown in FIG. 3.

In Step C4, the operator confirms. that the frontal and lateral arms 20and 30 have been moved to the frontal and lateral arm parking positionsshown in FIG. 3, and then the operator depresses a CT gantry movingswitch provided on the control apparatus 50.

In Step C5, decision is made whether the CT gantry 40 interferes withthe frontal arm 20, lateral arm 30 or top plate 11 when the CT gantry 40is moved to a CT imaging position which lies in the longitudinaldirection of the top plate 11 as shown in FIG. 3. If interference doesnot occur, the process goes to Step C6; otherwise to Step C7.

In Step C6, the CT gantry 40 is moved to the CT imaging position shownin FIG. 3. Then, the process is terminated.

In Step C7, warning is given that the movement is not permissiblebecause of interference. Then, the process is terminated.

FIG. 3 is a perspective view in which the frontal and lateral arms 20and 30 are moved to the frontal and lateral arm parking positions andthe CT gantry 40 is moved to the CT imaging position.

Because the frontal and lateral arms 20 and 30 have been moved to thefrontal and lateral arm parking positions, the CT gantry 40 can be movedto the CT imaging position without interfering with the frontal andlateral arms 20 and 30. Then, CT imaging can be performed by the CTgantry 40 at the CT imaging position.

According to the biplane angiography/CT apparatus 100 of the firstembodiment, since the lateral arm 30 for performing angiographic imagingin a lateral plane is provided in addition to the frontal arm 20 and theCT gantry 40, simultaneous angiographic imaging in two planes , frontaland lateral, is possible. Moreover, when angiographic imaging is to beperformed, the CT gantry 40 is retracted to a position not hindering theangiographic imaging and the frontal and lateral arms 20 and 30 aremoved to an angiographic imaging position, and when CT imaging is to beperformed, the frontal and lateral arms 20 and 30 are retracted topositions not hindering the CT imaging and the CT gantry 40 is moved toa CT imaging position. Thus, even when movement of the top plate 11 isminimal, interference of the frontal and lateral arms 20 and 30 with theCT gantry 40 can be prevented, and simultaneous angiographic imaging intwo planes, frontal and lateral, and CT imaging can be alternatelyperformed. Furthermore, since the movement of the top plate 11 isminimal, the subject is protected from discomfort, and additionallysafety is improved.

SECOND EMBODIMENT

FIG. 6 is a perspective view of a biplane angiography/CT apparatus 300in accordance with a second embodiment of the present invention.

The biplane angiography/CT apparatus 300 has generally similarconfiguration to that of the biplane anglography/CT apparatus 100 of thefirst embodiment, and portions having similar configuration will not bedescribed. Particularly, the present embodiment is configured so that alateral arm 130 comprised of an X-ray tube 132, an X-ray image receivingdevice 131 and a lateral C arm 133 horizontally moves in the transversedirection of the top plate 11 along a ceiling rail 135, and a CT gantry140 comprising an X-ray tube 141 and an X-ray detector 142 horizontallymoves in the longitudinally direction of the top plate 11 along floorrail 145.

Also in this configuration, since the lateral arm 130 for performinganglographic imaging in a lateral plane is provided in addition to thefrontal arm 20 and the CT gantry 140, simultaneous anglographic imagingin two planes, frontal and lateral, is possible. Moreover, whenangiographic imaging is to be performed, the CT gantry 140 is retractedto a position not hindering the anglographic imaging and the frontal andlateral arms 20 and 130 are moved to an angiographic imaging position,and when CT imaging is to be performed, the frontal and lateral arms 20and 130 are retracted to positions not hindering the CT imaging and theCT gantry 140 is moved to a CT imaging position. Thus, even whenmovement of the top plate 11 is minimal, interference of the frontal andlateral arms 20 and 130 with the CT gantry 140 can be prevented, andsimultaneous anglographic imaging in two planes, frontal and lateral,and CT imaging can be alternately performed. Furthermore, since themovement of the top plate 11 is minimal, the subject is protected fromdiscomfort, and additionally safety is improved.

THIRD EMBODIMENT

FIG. 7 is a perspective view of a biplane angiography/CT apparatus 400in accordance with a third embodiment of the present invention.

The biplane angiography/CT apparatus 400 has generally similarconfiguration to that of the biplane angiography/CT apparatus 100 of thefirst embodiment, and identical portions will not be described.Particularly, the present embodiment is configured so that a CT gantry240 comprising an X-ray tube 241 and an X-ray detector 242 horizontallyturns along an arc-like floor rail 246 between a CT gantry parkingposition, as shown in FIG. 7, at which the CT gantry 240 does notcollide with the top plate 11 moved in the longitudinal direction, andwhich is a position apart from the top plate 11 in the transversedirection by a certain distance, and a CT imaging position (not shown)at which CT imaging can be performed.

OTHER EMBODIMENT

The present invention may include an arc-like ceiling rail along whichthe lateral arm may horizontally turn between a lateral arm parkingposition and an angiographic imaging position.

Many widely different embodiments of the invention may be configuredwithout departing from the spirit and the scope of the presentinvention. It should be understood that the present invention is notlimited to the specific embodiments described in the specification,except as defined in the appended claims.

I claim:
 1. A biplane angiography/CT apparatus comprising: a top plate for laying a subject; a frontal arm comprising an X-ray tube and an X-ray image receiving device for performing angiographic imaging vertically across the subject laid on said top plate; a lateral arm comprising an X-ray tube and an X-ray image receiving device for performing angiographic imaging horizontally across the subject laid on said top plate; a CT gantry comprising an X-ray tube and an X-ray detector for performing CT imaging on the subject laid on said top plate; and control means for retracting said CT gantry to a position not hindering angiographic imaging and moving said frontal and lateral arms to an angiographic imaging position based on a command by an operator, and for retracting said frontal and lateral arms to positions not hindering CT imaging and moving said CT gantry to a CT imaging position based on a command by the operator.
 2. The biplane angiography/CT apparatus as defined by claim 1, wherein said control means is provided with a switch for the operator to input the command to retract said CT gantry to the position not hindering the angiographic imaging.
 3. The biplane angiography/CT apparatus as defined by claim 1, wherein said control means is provided with a switch for the operator to input the command to move said frontal and lateral arms to the angiographic imaging position.
 4. The biplane angiography/CT apparatus as defined by claim 1, wherein said control means is provided with a switch for the operator to input the command to retract said CT gantry to the position not hindering the angiographic imaging and to move said frontal and lateral arms to the angiographic imaging position.
 5. The biplane angiography/CT apparatus as defined by claim 1, wherein said control means is provided with a switch for the operator to input the command to retract said frontal and lateral arms to the positions not hindering the CT imaging.
 6. The biplane angiography/CT apparatus as defined by claim 1, wherein said control means is provided with a switch for the operator to input the command to move said CT gantry to the CT imaging position.
 7. The biplane angiography/CT apparatus as defined by claim 1, wherein said control means is provided with a switch for the operator to input the command to retract said frontal and lateral arms to the positions not hindering the CT imaging and to move said CT gantry to the CT imaging position.
 8. A biplane angiography/CT apparatus comprising: a top plate for laying a subject; a frontal arm comprising an X-ray tube and an X-ray image receiving device for performing angiographic imaging vertically across the subject laid on said top plate; a lateral arm comprising an X-ray tube and an X-ray image receiving device for performing angiographic imaging horizontally across the subject laid on said top plate; a CT gantry comprising an X-ray tube and an X-ray detector for performing CT imaging on the subject laid on said top plate; top plate moving means for allowing said top plate to horizontally move in its longitudinal direction; frontal arm swiveling means for allowing said frontal arm to swivel around a certain axis; lateral arm moving means for allowing said lateral arm to move in a certain direction; and CT gantry moving means for allowing said CT gantry to move in a certain direction.
 9. The biplane angiography/CT apparatus as defined by claim 8, wherein said lateral arm moving means horizontally moves said lateral arm in the longitudinal direction of said top plate, and said CT gantry moving means horizontally moves said CT gantry in the transverse direction of said top plate.
 10. The biplane angiography/CT apparatus as defined by claim 8, wherein said lateral arm moving means horizontally moves said lateral arm in the transverse direction of said top plate, and said CT gantry moving means horizontally moves said CT gantry in the longitudinal direction of said top plate.
 11. The biplane angiography/CT apparatus as defined by claim 8, 9 or 10, wherein said lateral arm moving means rotates said lateral arm around the longitudinal direction of said top plate.
 12. The biplane angiography/CT apparatus as defined by claim 8, 9, or 10, wherein said CT gantry moving means horizontally turns said CT gantry.
 13. The biplane angiography/CT apparatus as defined by claim 8, 9, or 10, wherein said lateral arm moving means horizontally turns said lateral arm.
 14. The biplane angiography/CT apparatus as defined by claim 8, wherein said lateral arm moving means is configured to swing said lateral arm up to a ceiling.
 15. The biplane angiography/CT apparatus as defined by any one of claims 1-10 or 14, wherein said top plate is configured to be vertically movable.
 16. The biplane angiography/CT apparatus as defined by any one of claims 1-10 or 14, wherein said top plate is configured to be horizontally rotatable.
 17. A biplane angiography/CT apparatus comprising: a top plate for holding a subject in a horizontal position; a frontal arm comprising an X-ray source and an X-ray image receiving means for performing angiographic imaging vertically across said subject; a first rail means disposed above said top plate; a lateral arm movably held on said first rail means and comprising an X-ray source and an X-ray image a receiving means for performing angiographic imaging horizontally across said subject; a second rail means disposed on a surface below said top plate; a CT gantry movably disposed on said second rail means and comprising an X-ray source and an X-ray detector for performing CT imaging on said subject; and control means for moving said CT gantry on said second rail means to a position not hindering angiographic imaging and for moving said lateral arm on said first rail means to perform an angiographic imaging based on a command by an operator, and for moving said lateral arm on said first rail means to a position not hindering CT imaging and for moving said CT gantry on said second rail means to a CT imaging position based on a command by said operator. 